If your a native speaker, your welcome to provide textual
corrections. Translations or partial translations are also most
welcome.
Introduction

"Hallo Northern Sky"
or HNSKY is a full feature planetarium program for MS-Windows.
Free with 30.000 deep sky objects and star databases up to magnitude
16. Online access to Gaia, UCAC4 en NOMAD star catalogs Access to
local GSC 1.2 or the USNO
UCAC4 catalogs. The Sun, Moon, the planets and their major
moons are all displayed with surface features. It maps the position
of comets and asteroids with online updating. It comes with hundreds
of DSS deep sky images which will blend in at the correct size and
orientation. It has a powerful animation menu.
and an integrated deep sky observations
help file and 21 non-English menus. It can control almost any
telescope using the ASCOM interface
program.

Downloading of additional DSS images via the internet is fully
integrated. Just select an area and select download. After a few
second the DSS image will blend in the HNSKY map at the correct size
and orientation.

The comet or asteroid database can be updated online with just one
click. You can also import orbital elements from JPL
Horizons.
Online database search for objects in the selected area.

Numerical integration for asteroids to achieve
highest accuracy positions years in the future or past. The error is
less then 1" after 10 years !!! So a asteroid orbital elements from
10 years ago will after numerical integration allow position
calculation within 1" accurate!! So also 10 years in the future.

The intention of the program is to familiarise you with the night
sky and prepare yourself with a map for a night with your telescope.
To help you with this, all deep sky objects are displayed in the
correct size and orientation if available.

This program is free. Please distribute and enjoy it. Let me now if
you liked it. Comments are always very welcome. This program stays
Han Kleijn and you may not make money from it. Please distribute
with original files only.

"Hallo" is the Dutch version of Hello.

Overview of the sky in "Azimuthal equidistant projection":

Under the main menu "HELP" the following quick overview is
available:

Visibility of planets:
Yellow indicates if the planet is visible. The vertical axis are the
next 31 days. The horizontal axis indicates the time from 17:45
hours up to the next morning 6:15 hours in steps of 15 minutes.

Dark night's (no Moon) are indicated as
follows:
The vertical axis are the next 31 days. The horizontal axis
indicates the time from 17:45 hours up to the next morning 6:15
hours in steps of 15 minutes.

Before the program show the sky correctly, you have first to set
your location and time zone correctly

In menu SETTING (main menu FILE, sub menu
SETTINGS or CTRL-E) tab Location you will see the
following:

Location: You will notice a small red circle indicating the
position on earth surface. The image on the left is showing the user
location (7 degrees east, 50 degrees north in the Netherlands, Note
the mouse geographical position will be shown the right bottom
corner.

Time zone: The vertical yellow line is a help for checking if
you have entered the time zone correctly. In the map it is
indicating where the Sun is exactly at it's highest point at mid day
and at the middle of the night is at 12 PM. So the red circle of
your location and the yellow line zone should be close. In other
words, the yellow line is indicating the middle of the time zone.

For USA en Europa the main time zones are available. If one of these
is selected the daylight saving compensation will be automatic
following the current definitions.

If your time zone is not available select the hourly difference with
UTC time. See table below.

Daylight savings: In most countries during the summer the
clock is set one hour forward. This is called daylight saving or
summer time. To correct for this change, put check mark at "DAYLIGHT
SAVING" if applicable. If daylight saving is active the map time
hour/minutes separator is a dot as "23.00" else time is indicated as
"23:00".

To save these location settings, select from the pull down menu "FILE"
and then "SAVE STATUS". The location settings will be saved
in the file DEFAULT.HNS. This settings file is automatically loaded
after start-up

Now you ready are with the setup. The only other thing to do is to
set the time. You could set "follow the system time" and HNSKY will
use the time of the computer for creating the sky map. However if
you preparing for an observation night, maybe it is better to set it
at midnight. The following options are available:

Main pull down menu "DATE" allows following time settings:

Follow computer clock. The map is updated regularly at an
interval set in "SETTINGS" , TAB
SETTINGS.

Tonight, the map is made for midnight 12 PM

Now, Map is made for current computer time but does not
change

Enter date time, Enter any time in past or future.

Starting with version 3.0.2 the main menu is customizable. You can
call up this pop-up menu with the right mouse button or by clicking
on the triangle button on the right as shown below. Save the
settings to make it permanent:

With the SEARCH option, Alt-F, it is possible to search through the
entire database. To find deep sky and solar object as NGC104,
IC1396, M42 or the Moon, their full name should be entered. To find
SAO, PPM and TYCHO stars enter their catalog number only. The text
search of Tycho files and other .290 files goes from north to south
and could be a bit slow. SAO and PPM and other DAT star files are
organized from bright to faint and a text search for bright stars is
faster. For each object only one name will be displayed on the map.
Preference is given to the Messier name rather then NGC. So a search
for object NGC1952 will display M1 on the map.

The search menu allows wildcards. If you type a search string such
as PAN* and press the button COMETS, it will list all comets
complying to this wildcard as 253P/PANSTARRS. Alternatively you
could first press the button COMETS, then type the search string
PAN* and finally hit Go To button. The combo box will list all
comets complying to this wildcard.

The top part "Stars" allows the selecting the star database
and adjustment of star boldness and the number of stars displayed
called density option. The primary star database is used for wide
field displays. If selected, the secondary kicks in at high zoom
factors.

The TYC as primary database is included. If you require more stars
download and install the new primary U16 a hyrbrid of the
Tycho and UCAC4

Alternatively you could download and select (settings) the UCAC4 local for secondary.
In some cases in the transition phase the corners could be without
stars. Note that the primary U16
will have the same amount of stars as the UCAC4 and allow 360
degrees view. The benefit of a local copy of the USCAC4 will
only be some more star information, proper motion but limit field of
view. The U16 will be replaced in April 2018 by local Gaia DR2
version.

The reason for this dual setup is speed. For wide field it is
convenient to sort the star database from bright to faint, so the
few thousand brightest stars can be quickly accessed. All HNSKY
native database are organized in this way. For large catalogues
going very deep with many faint stars, the sorting is done on
location to allowing quick access for a small area. The result is
that it is a rather difficult the extract the few thousand brightest
stars up to magnitude 5 from an original UCAC4 catalogue sorted on
declination and 9 gigabytes large.

The bottom part"Deep sky + solar" allows selection of the
deep sky database and two supplements in
parallel. For most beginners the "Deep sky level 1" is sufficient.
The database can be filtered on magnitude, size and type. At the
bottom there are two sliders to adjust the background and brightness
of the displayed deep sky images (FITS files) Normally you don't
have to adjust them but some deep sky DSS pictures are
under-overexposed and need some fine-tuning to get maximum detail.

The bottom part has a second TAB for three more supplements, the
TOAST projection of the whole sky for displaying the Milky-Way
(slow, use with care).

This TAB has one special option to filter out near-Earth object
(NEO), both asteroids and comets closer then 0.05 a.u. to Earth.
This is the only option which can not be saved by purpose.

This menu allows to move directly to a position on the map. The
North, South, East, West or Zenith buttons move straight to overall
view in that direction. You can enter numbers with decimal fractions
in all fields including the degrees and hours.

On the right bottom you can paste a position from Simbad
or any other source. It will accept four or six string positions.
All text will be removed. An "S" (=South) will introduce a minus
sign. The following two examples will be interpreted correctly:

Left mouse button:
1) Display data of the object near the cursor.
2) If cursor is close to the borders of the window, move left,
right, up or down.

Right mouse button:
This will introduce a mouse pop-up menu with several options. While
holding the right button you can also pull a rubber square which
will be the area for the following:

Search for objects in the area selected in Simbad, Hyperleda or Ned
or internal. If no area is selected search near mouse position. The
Simbad, Hyperleda and Ned will create a search request in the
default web browser. The internal search will produce a list in new
window. Relevant data could be copied-pasted.
If a planet is within the internal search area, the J2000, mean
and apparent positions will be given.

Download from internet deep sky image defined by the square or
near mouse position. HNSKY will store up to 9 images in the Documents directory as download1.fit,
download2.fit.... After 9 files it overrides the first to prevent
creating too many files. Normal DSSor DSS2
images are download as defined in the internet setting in menu SETTINGS tab 4.

For wide fields with a height above 3.5 degrees, Skyview provide
the
Axel Mellinger low resolution survey. The images are shown
at any zoom and stored as downloadM1.fit, downloadM2.fit.... You
can select in the internet setting in menu SETTINGS tab 4 an other survey like
"HALPHA" or Mellinger colour green (MELL-G) or blue (MELL-B)

1) Click the mouse wheel as a button,
2) Pushing ALT KEY plus RIGHT or LEFT
MOUSE button.
////3) Click twice with the LEFT mouse
button.//// (remove 2018)
Mouse wheel:

Use the mouse wheel zoom in or out. To zoom in on a specific
object, pull square box using the mouse while holding the left
mouse button down. Use CTRL+Z to return to previous view. The
distance and angle are give in the status bar. Clicking the mouse
wheel as button will centre the map on that position

Keyboard:

Beside the ALT+key options for accessing the pull down menu items,
the following hot keys are available in the pulldown menu:

Step 23:56 hours. This is very useful
when monitoring a solar object over a long period
while the star field reins stationary.

Some areas in the canvas can be clicked on. If a field is active,
the mouse pointer will change to the standard arrow. There is an
area at "date" to change the date, "position" to move to an other
position.
/////If you want to know when an object is in the zenith, hold the
mouse steady at the rise and set times. See below:////
remove 2018)

Copy object information in the clipboard.

After an object information is displayed, it can be copied to the
clipboard by clicking on the status bar. Abbreviations
are unconverted from the deep sky database.

Location use: This one should be selected for accurate
positions of planetary object.

Equinox: Select for the map equinox J2000. The telescope
equinox will be set by ASCOM. The equinox 2000 is the common
reference frame for maps and this one should normally be selected.
An astronomical reference
system has conventionally been the extension of the Earth's
equatorial plane, at some date, to infinity. If you use
HNSKY to control a telescope, you can either select for the map
"mean equinox of date" or keep equinox J2000 selected but the
communication for telescope should be in most cases "mean equinox
of date". HNSKY will read and select automatically the correct
setting from ASCOM communication if provided. Note that if a
telescope is correctly polar aligned the mechanical drive will
follow this "equinox of date" as the earth rotation does the
same. See topic equinox in glossary
and telescope control.

Screen: If in main pull down
menu DATE is set follow system time, the update interval
is set in tab SETTINGS, tab Settings, part Screen.
Typical you should set this at 5 minutes. If you select 0 minutes,
the actual interval will be 1 second for animation. Planetary
objects will now move in real-time with an update frequency of one
second. This will create a high CPU load on your computer.

Screen mode:This should normally be selected. If selected
the sky map is created in memory and displayed instantly.

GSC location: Normally on binary version should be
selected. Download the GSC_ACT using an FTP program keeping the
directory structure intact see webpages.
Since it is organized in several directories and thousands of
files, using an FTP program such as FileZila is the only option.
Note the GSC can be used for small fields
only. For background information see GSC

USNO location:webpages. Note the UCAC4 can be used for small fields only. For
background information see UCAC4

FITS image file settings This is the path to the FITS files
of the deep sky and planetary images. The dot in the example
represent the "Documents" folder.

Jet Propulsion Laboratory
Development Ephemeris: For the highest
planetary position accuracy download the DE430 or DE431
file. The blue arrow will give the download link or download from
here. You could place the ephemeris file in
the "Documents\hnsky" folder or program folder typically \Program
files\hnsky . The small lnxp2000p2000p2050.430 file is covering
the years 2000 to 2050. The huge lnxm13000p17000.431 (2.8gbyte) is
covering the years -13000 to 16999.

If the JPL ephemeris is working correctly, you will see the
letters DE in the blue title bar of HNSKY. If not the status bar
will show a message "JPL... not found/invalid range". This message
could be overwritten depending what you are doing. If the date is
outside the valid range, the letters DE will disappear and the
same status bar message "JPL... not found/invalid range" will be
given.

There is a possibility to use two JPL ephemeris files. One small
at position 1 with small date range and one with a large range at
position 2. Even with the huge DE431 at position 1, the program is
quick. The program will first try to use position 1, then position
2 and if no file is found or the date is outside the valid range
it will fall back on the internal analytical solution. The
internal analytical solution is only accurate between years 1750
and 2250. Only one JPL ephemeris file is sufficient.

Documents path indicates where the FITS, supplements en
cache files are stored. See requirements.
This is normally the "hnsky" folder in the Documents folder. The
installer will normally place user files in this folder. If this
folder is not available, it will alternatively it will look for
the files in the program folder. Note that under Win10 writing in
the program folder is not possible and could block downloading DSS
images and accessing online star databases unless the permissions
of the HNSKY program folder are modified. So it is better to have
the "hnsky" folder in the Documents folder.

Colors: The grid, constellations,
solar and deep sky colors and font size can be set in the menu "SETTINGS"(CTRL+E)
of main menu "FILE".

Go to "PAGE" colors and just click with the mouse on the
colors to change them.

The menu colors as any other window application are defined in
your Windows set-up. To change these color settings, select "SCREEN"
in your Windows set-up.

To prevent blinding and loosing your "night vision", a menu option
"NIGHT VISION" is available under the main menu "SCREEN".

Some laptops/computers do not display text in the status bar
correctly in night vision mode. A way around is to change in the
windows setup, the text color of 3D-objects. (OK button in windows
setup, screen color menu.) Change for example the text color from
black to blue.

All these settings become permanent after selecting "SAVE
STATUS" in menu "FILE".

The only thing you could change are parameters. You could change
DDS2R (Second Deep Sky Survey red) to DSS2B (blue) or DSSR (First
survey red). Each provider has a slightly different interface so
changing the provider will not work.

From this tab the asteroid and comet database can be quickly
updated. Same is possible within the editor.

The internet address for the asteroid ephemerides database (The
SKY format) contains the current year. HNSKY will update the
year in the path automatically based on the computer clock. In the
first days of a new year it is possible that the update is not
available yet from the minor
planet center webpage. Is this the case, modify manually the
year to the previous year. Note you can also the numerical
integration option in the asteroid editor to update the
ephemerides data.

For HNSKY versions compiled with FPC an INDI
interface is available both for Linux and Windows versions. INDI
is mainly used in Linux however the FPC version of HNSKY for
MS-Windows can control a telescope mount remotely via a local
Linux server using INDI.

A local Linux server can be started with a telescope driver
using a command
line or conveniently with the utility INDI
starter. Two different setups could be used:

Server and HNSKY client in same computer: Enter for
the INDI server address "localhost" or 127.0.0.1. Port should be
7624.

Server and
HNSKY client in different computers: Enter the
TCP/IP address of the server. To find this address type in
a Linux terminal the command IFCONFIG. Take the
(IP4) inet addr. of eth0. Port should be 7624.

The INDI client is used for settings of the telescope mount
driver. Most mount drivers have a simulation mode which can be set
for testing. To use the simulation mode of the mount driver you
have to set it "ON" in the INDI client before it is possible to
connect the mount. You could also use the generic telescope
simulator for testing.

The "MARKERS AND LINES" allows you to draw deep sky outlines or
your personal horizon and are stored in supplement 2.

Usage:

- Click on an existing object to use that name. (optional)
- Activate "DRAW LINES (Ra/DEC)"
- Click on the outlines of a deep sky object. Each time a line
will be drawn.
- When finished deactivate "DRAW LINES (Ra/DEC)"
- Open supplement 2 and save outline as a .SUP file.
- When required last lines can be deleted with "DELETE LAST
POINT".

Any change is not saved and requires a manual save of supplement 2
!!

Editing commands:

Line colour change mode: After activating this mode, hit
the end point of a line and on every click the colour changes.

Insert line mode: After activating this mode, hit the end
point of a line and on next click an extra line is inserted at
that next point.

Remove line mode: After activating this mode, hit the end
point of a line and the line is marked as comment with ;$$$ in
front.

Hide line: After activating this mode, hit the end point of
a line and the line command is changed from "line to =-1 to "move
to"=-2 or the other way around. Works also for Az/Alt lines.

Be aware the the line commands are a series. For example these
three commands will draw two lines:
1) "move to point A", 2) "line to point B", 3) "line to point C".

If you remove a start point of a constellation e.g. "move to point
A", A new line from somewhere will pop-up to "point B". You have
to apply the hide line on "point B" to make it a "move to point B"
to remove this line.

1) Sidereal view off (=Terrestrial view:
- Stars rotate around celestial north (Polaris) as time goes by.
- Altitude and horizon grid are fixed as time goes by.
- RA/DEC grid follows stars and rotates around the celestial north
as time goes by.
- In the short term solar objects are going around similar as
stars.

Terrestrial view is what you see if you just look to the sky and
is caused by the rotation of the earth.

2) Sidereal view on:
- Stars are fixed on the map as time goes by
- Altitude and horizon grid rotate as time goes by.
- RA/DEC grid is fixed.
- Solar objects are moving slowly on the fixed map.

Sidereal view is what you see through the telescope while having
the sidereal drive on. The so called diurnal motion of stars is
off.

3) In the third option is to follow planetary object in the Animation Menu.

To activate this menu, select via menu "SCREEN", "ANIMATION"
(Ctrl+R). You could activate and use the animation button in the
menu.

The animation menu handles three topics:

1) Object to follow: Follow a planetary object or the
stars (sidereal) or nothing (terrestrial
view) while time changes.

2) Time step: Change the time in a single or many steps.
The many steps or animation are started with the "<<" or
">>" button. If tracks is activated the planets make a track
for every step. The forward animation ">>" can be also
started with key "INS" (or with menu "SCREEN", "INSTRUMENTS",
"DRAW SOLAR OBJECTS")

3) Find an eclipse or occultation:
This will show for your location the next or previous eclipses or
occultation s. For the lunar option, all planets and the bright
star Aldebaran are checked against the Moon position. For the
solar option, the position if the Moon, Mercury and Venus are
checked against the Sun position. The date and time show are just
for the start of the phenomena.

The solar combo box list list will be filled with up to 10 object
names where you click on.

To make animated movies, you should use an additional screen
recorder program.
if you want to make a movie of Jupiter and its moons do the
following:

1) Lock on Jupiter by typing or clicking
on Jupiter and activated option "Solar".
2) Set the date to the beginning of the
event.
3) Select a small step size e.g. 1 minute
and duration of 500 steps.
4) Hit the ">>" or key "INS" to
animate.

It could be beneficial the orientate the top of the MAP to the
North by menu "SCREEN", "NORTH ALWAYS UP"
(Ctrl+Alt+N)

HNSKY can work together with ASCOM, a free third party telescope
interface. ASCOM has drivers for almost any telescope. First you
have to download and install the ASCOM program from http://ascom-standards.org

As soon you activate the ASCOM interface by the right mouse button
pop-up menu or CTRL+7, the ASCOM window will pop-up. This window
will allow telescope selection. For testing purposes you could
select the ASCOM telescope simulator. Please select "Telescope
simulator for .NET" rather then the older "Simulator".

Equinox: The telescope position will become visible
as a cross. For maximum accuracy, the telescope and HNSKY should
communicate in the same coordinate system. See menu SETTINGS (CTRL+E), setting EQUINOX,
TELESCOPE. Most controlled telescopes communicate in "mean equinox
of date" coordinates. HNSKY normally sets this automatically by
reading from the telescope the equinox used using the ASCOM
protocol. In this case you will not be able to change the
telescope equinox and the correct equinox for communication will
be used. Depending on the indication in your telescope you could
select for the map either "mean equinox of date" or J2000 till
they indicate the same. See menu SETTINGS
(CTRL+E).

Note that if a telescope is correctly polar aligned, the
mechanical drive will follow this "equinox of date" as the earth
rotation does the same. For this reason it is convenient to
communicate in "mean equinox of date" coordinates rather then do a
conversion in the telescope to a different epoch.

The telescope position is indicated in the top caption of the
HNSKY window.

Sync to mouse position, matches the telescope's coordinates
to the mouse position.

Abort slew, Stops a slew in progress.

Follow solar object, let telescope follow object on canvas
refresh. Object selection by mouse click. To enable this function
switch on "follow time" in the pull down menu and "frequency of
screen update" in menu SETTINGS, tab SETTINGS to one minute.

If the "frequency of screen update" is set to zero the interval
will be not zero minutes but one second. This could be used to
track a comet, Moon or any other solar object on it's calculated
track!!. HNSKY will send every second and new calculated position
to the telescope. If the telescope mount has an accurate polar
alignment, this could be used for a long time exposure of a comet
without the need for stacking. This could be called MATH
GUIDING. To reduce the computer load it could be beneficial
to switch of star and deep sky database.

A better solution is to guide on a nearby star with a program like
PHD2 and set the comet diurnal motion offset in PHD2. HNSKY will
give the velocities of comets and asteroids in arc sec/hour in the
status bar which could be entered directly in PHD2 for that
purpose.

Track telescope, Map will follow telescope.

Connect to telescope, connect via ASCOM driver to the
telescope.

If you double press the left mouse button while holding the
CTRL key down the telescope with go to the mouse position. (2018)

HNSKY FPC version has a TCP/IP server which can communicate with astro photography tools as APT & CCDciel
(both in near future). To activate put a check mark in front
of "use TCP/IP server" in the menu SETTNGS (CTRL-E).

Azimuthal equidistant projection. For a better over all
view of the sky, the "azimuthal equidistant projection" is
available. This projection method allows very wide views up to
almost to 360 degrees. The radial distances and direction measured
from the centre of the map are correct but the disadvantage is a
distortion for large fields of view.

You could select a RA/DEC or Alt/Az grid for orientation. The
horizon is shown as a double thick line.

Orthographic or spherical projection method. The sky is
projected on a sphere and in the middle of this sphere lies the
Earth. You are observing from outside this sphere with the
corrected left and right orientation. This projection method
allows wide views almost to 180 degrees. Disadvantage near the
edge there is a distortion.

Printing. The printing routine will rebuild and adapt the screen
view to the printer resolution. Laser printers will produce sharp
and good quality prints. The size of the window and monitor
resolution are irrelevant.

From version 3.2.2b the size of the printed stars is no longer
adapted to the DPI resolution of the printer. A low resolution of
of 72 or 144 DPI will give the correct star size (a few pixels)
for printing on paper. If you select 1200 DPI you will get much
smaller stars (still a few pixels), more intended for zoom-able
digital maps. You could use this for printing to PDF

The are two print options: Black stars on a white background or
inverse white stars on a black background. If the print option
"white background" is selected, the intensity of colors will be
adopted accordingly. For example, a very bright yellow Moon in a
black sky will be adapted to a white sky as very dark yellow Moon.
Identical as white stars become black on a white background.

Another option is to copy the screen contains to the windows
clipboard using CTRL+C or the menu option "COPY WINDOW TO
CLIPBOARD" in the main menu "SCREEN". Then paste it (CTRL V) in
your favourite graphic program for further processing as saving or
printing. With this option the resolution is depending on the
original HNSKY window size.

A third option is to use the standard Window feature to copy the
complete window in the windows clipboard by using the ALT-PRINT
SCREEN keys. This will capture the complete window including menu
bar. Then paste it (CTRL+V) in your favourite drawing program.

Deep sky observations help file for use with the HNSKY planetarium
program. It is a compilation of more then 10.000 visual
observations by Steve Gottlieb, Steve Coe and Tom Lorenzin. In
HNSKY after you found an object or clicked on it, just hit the F2
button and the CHM file will display the available observations of
that object. Rather then F2, you can go the main menu HELP and
select the second menu indicating the last object found. Or just
look around in the index of the deepsky.chm file.

Here an overview of the available star database and accessible
catalogues:

Star databases:

Local star
databases

Name

Abbreviation

Magnitude limit

Type

Size

Maximum
field
in HNSKY

Proper motion

Description and download link

TYC++

TYC

12.5

Local files, native 290-10 format

50 MB

360°

No, epoch
2017

Native HNSKY star database up to magnitude
12.5 containing 4.7 million stars. compilation from
TYCHO-2 UCAC4. Included with the program and installed.

TUC

TUC

15

Local files, native 290-9 format

206 MB RAR

360°

No, epoch
2017

Native
HNSKY database up to magnitude 15 containing 39
million stars. Compilation from TYCHO-2 and UCAC4.
Contains the Tycho and UCAC star labels/designation.
Unpack in the program directory, typically c:\program
files\hnsky.

U16

U16

16

Local files, native 290-5 format

419 MB RAR

360°

No, epoch
2017

Native
HNSKY database up to magnitude 16 containing
113 million stars. A compilation of UCAC4 and Tycho-2. No
Tycho-2 or UCAC identifiers/designations
are available due to small 5 byte record size. Instead an
IAU style designation based on the position is used.
Unpack in the program directory, typically c:\program
files\hnsky

GAIA

G17

17

Local files, native 290-5 format

647 MB RAR

360°

No, epoch
2017

Native
HNSKY database up to magnitude 17 containing 164
million stars. Note that Gaia DR1 is missing some stars so
is less suitable for star maps. Unpack in the
program directory, typically c:\program files\hnsky

UCAC4

UC4

16

Local files, external USNO
format

8.4 GB

2.6x1.3°

Yes

UCAC4: You can download the 113 million
stars, 8.5 Gbytes large USNO
UCAC4 from
ftp://cdsarc.u-strasbg.fr/cats/I/322A/UCAC4/ HNSKY
can access this catalog directly. Download Z001 to Z900
from the U4b directory and add to the same directory file
u4index.unf from U4i. This UCAC4 and Nomad are the
catalogues where HNSKY will use proper motion for maximum
accuracy. See HNSKY UCAC
screenshots.

GSC 1.2

GSC

15

Local files, external format

303 MB

16x14°

No, epoch 1982 & 1975

Obsolete: GSC, HST Guide Star Catalog: The
GSC_ACT
or (catalog 255) GSC 1.2
(catalog 254) of 15 million stars to about magnitude 15 is
available at CDS in the compact binary format (303 MB).

The USNO UCAC4 includes positions, proper
motions and magnitudes for 113 million objects

Gaia

G

21

online

-

1.4x0.8°

Yes

Gaia DR1

Nomad

N

21

online

-

1.4x0.8°

Yes

NOMAD is merged catalog compiled by the
USNO, with positions and magnitudes for 1.1 billion stars
from several source catalogs, including Hipparcos,
Tycho-2, UCAC 2, and USNO-B 1.0

PPMXL

P

20

online

-

1.4x0.8°

Yes

PPMXL is a catalog of positions, proper
motions, 2MASS- and optical photometry of 900 million
stars and galaxies, aiming to be complete down to about
V=20 full-sky. It is the result of a re-reduction of
USNO-B1 together with 2MASS.

URAT

U

18.5

online

-

1.4x0.8°

Yes

By USNO, northern sky only, extends down to
Declination -15°.228 million objects

The supplements
can be freely modified in the main editor. For convenience
HNSKY provides and additional edit menu to access a single entry:

After an object/entry of a supplement is found, it is possible to
edit the entry by moving&click the mouse in the info area at
the left top of the screen. In the field "type" additional info as
a log could be entered. Select "Save suppl" to make the change
permanent. This works only for supplements not for the
database(s).

New entry:

The
menu-shortcut "HOME" key or via popup menu "Markers
and lines, "Add object", will add a marker to the second supplement.
In the supplement a line will be added with the mouse position,
supplement line number and date. You could
use the above menu to add an observation in the field "type".
This marker & observations are only permanent after saving the
supplement.

In the supplement the entry "_56" with the observation could look as
follows:

The spectral types of stars are defined with two characters. The
first defines the main spectral type as follows:

Class letter

Temperature

Conventional color description

Actual apparent color

O

≥ 30,000 K

blue

blue

B

10,000–30,000 K

blue white

deep blue white

A

7,500–10,000 K

white

blue white

F

6,000–7,500 K

yellow white

white

G

5,200–6,000 K

yellow

yellowish white

K

3,700–5,200 K

orange

pale yellow orange

M

2,400–3,700 K

red

light orange red

The main types grade are subdivided decimally as: A0, A1, A2, A3,
A4, A5, A6, A7, A8, A9, F0, ....
There are also some special spectral types as R, N, S, C for the
carbon stars, W for the Wolf-Rayet stars and Q for novae

The Saguaro Astronomy Club or SAC deep sky database contains as
good as all deep sky objects visible in amateur telescopes.
The SAC compilation of data was begun in an effort to provide a
comprehensive observing list for use at the telescope. Their data
is released for private use by anyone who wishes to use this
database.
Please do not sell this database in any form. The database in
ASCII format can be download from their web
pages.
The HNSKY database is a compilation of the SAC DEEP SKY DATABASE
VERSION 8.1 and Wolfgang Steinicke NGC/IC
database.

HNSKY is using the updated and corrected version from May 1991,
available from the CDS. This star catalog
is complete to magnitude 9.0 but in some areas the limiting
magnitude was raised to magnitude 10. The original ASCII format is
converted to the HNSKY format

Since its appearance in 1966, the SAO Catalogue (SAO, 1966) has
been the primary source for stellar positions and proper motions.
Typical values for the rms errors are 1 arc sec in the positions
at epoch 1990, and 1.5 arc sec/century in the proper motions. The
corresponding figures for the AGK3 (Heckmann et al., 1975) on the
northern hemisphere are 0.45 arc sec and 0.9 arc sec/century.
Common to both catalogues is the fact that proper motions area
derived from two observational epochs only. Both catalogues are
nominally on the B1950/FK4 co-ordinate system.

The PPM Star Catalogue (Roeser and Bastian, 1991, Bastian et al.,
1993; for a short description see Roeser and Bastian, 1993)
effectively replaced these catalogues by providing more precise
astrometric data for more stars on the J2000/FK5 co-ordinate
system. Compared to the SAO Catalogue the improvement in precision
is about a factor of 3 on the northern and a factor of 6 to 10 on
the southern hemisphere. In addition, the number of stars is
increased by about 50 percent. Typical values for the rms errors
on the northern hemisphere are 0.27 arc sec in the positions at
epoch 1990, and 0.42 arc sec/century in the proper motions. On the
southern hemisphere PPM is much better, the corresponding figures
being 0.11 arc sec and 0.30 arc sec/century. The PPM catalogues
(ftp://cdsarc.u-strasbg.fr/cats/I/146,
ftp://cdsarc.u-strasbg.fr/cats/I/193) are available in ASCII
format from the Centre de Données
astronomiques de Strasbourg

Note: These ASCII catalogues can't be accessed by HNSKY directly
conversion. Converted version is already available!

The improvement over the SAO Catalogue was made possible by the
advent of new big catalogues of position measurements and by the
inclusion of the century-old Astrographic Catalogue (AC) into the
derivation of proper motions (for a description of AC see
Eichhorn, 1974). But even PPM does not fully exploit the treasure
of photographic position measurements available in the
astronomical literature of the last 100 years. The Astrographic
Catalogue contains roughly four million stars that are not
included in PPM. For most of them no precise modern-epoch position
measurements exist. Thus it is not yet possible to derive proper
motions with PPM quality for all AC stars. But among the 4 million
there is a subset of some 100,000 CPC-2 stars that are not
included in PPM. These stars constitute the 90,000 Stars
supplement to PPM.

==The Bright Stars Supplement (275 stars, 1993)==

A number of bright stars is missing from the PPM Star Catalogue,
both on the northern and on the southern hemisphere. The Bright
Stars Supplement described here makes PPM complete down to V=7.5
mag. For this purpose it lists all missing stars brighter then
V=7.6 mag that we could find in published star lists. Their total
number is 275. Only 2 of them are brighter then V=3.5 This
replaces the December 1992 edition of the Bright Stars Supplement
which inadvertently contained 46 duplicates of stars already
contained in the main parts of PPM.

Introduction: HNSKY has the ability to use the "Guide Star
Catalog" CD-ROM database version 1.1 or 1.2, commonly known as the
"GSC". This set of 2 CD-ROMs (one for the northern sky +90 till
-7.5 degrees, the other for the southern sky) contains
approximately 15 million stars. Limiting magnitudes about 15. The
Guide Star Catalog (GSC), which has been constructed to support
the operational need of the Hubble Space Telescope (HST) for
off-axis guide stars. It is one of the largest star catalog
currently in existence. It contains nearly 19 million objects
brighter then sixteenth magnitude, of which more then 15 million
are classified as stars.

Use of GSC in HNSKY:The GSC is divided in regions of about 2.5
degrees. HNSKY can display these regions combined till a practical
limit of about 20 degrees. Within this displayed area, the search
option will search and objects can be clicked on for more details.
Due to the fact that the GSC is not sorted by magnitude, a mouse
click could result in the data of a nearby but fainter object. To
prevent this, zoom in till there is enough distance between the
individual stars. The text search option Alt-S will find any GSC
star. It not too many regions are shown it will be faster.

The 15 million stars in the GSC are displayed in white. All other
4 million mainly "non-star" objects are displayed in green.

The location of the GSC CD's should be set in main menu "FILE",
sub menu SETTINGS. In case only one drive is available, set both
settings to that drive and swap CD's if required. The CD-north
covers +90 till -7.5 degrees declination.

The GSC is now considered obsolete for professional use and is
superseded by the much larger GSC II, but still very useful.

How to get the GSC:

The Guide Star Catalog (GSC1) was prepared by the Space Telescope
Science Institute (ST ScI), (the organisation which operates the
Hubble Space Telescope), and was sold through the Astronomical
Society of the Pacific (ASP) in San Francisco, California, USA.
The GSC is not supplied with HNSKY. Unfortunately the ASP GSC CD's
are discontinued. The only source known now is to download them
through the internet, see web pages Since
it is organized in several directories and thousands of files,
using an FTP program such as FileZila is the only option.

You do not have to download all the files. You can start with few
files around RA=0 and DEC=0 as files \N0000\0001.GSC (38 Kbytes
compressed ) . . 0002.GSC ... to have a look how it works. Put
them on your hard disk in the same directories (folders) as found.
The index files under \tables\regions.tbl are no longer required

HNSKY will operate with the original GSC 1.1 CD-ROMs in the ISO
9660 FITS format (issue date of 1 August 1992, 2 CD'S full) or
with the newer GSC 1.2
(303 Mbytes, dated 2001) provided in binary format from internet
or the GSC_ACT. HNSKY doesn't work with the "compressed" data
found on other CD-ROM astronomy programs.

Here is some important GSC information for people who download the
GSC from internet:

The star information is stored in *.GSC files.

They should be in the original directory or maps (steps of
declination):

The above structure should be kept on CD-ROM or hard disk. The
main directory is normally \GSC\ but can be set in menu
"SETTINGS".

For more information download the readme files from the Web Pages
mentioned above.

In the past the files from other servers where provided in *.GZ
format and have to be unzipped using GZIP (not PKUNZIP !) or
WINZIP. If the resulting filename is 0001_GSC, 0002_GSC... then
they should be renamed as 0001.GSC, 0002.GSC ....

The Tycho2++ is the standard star database used in the HNSKY
program. Format is in the 290 format. It
is made from the combined Tycho-2 and UCAC4
star catalogues free available from the CDS(Centre de Données
astronomiques de Strasbourg) webpage. The Tycho-2++ contains 4,7
million stars if which 2.5 million Tycho stars and additional
about 2.2 million UCAC4 stars to make it complete up to magnitude
12.5.

The reason the UCAC4 was not used completely is the poor magnitude
value for some bright stars. This compilation was created by
adding all UCAC4 star without an HIP, FK6 or Tycho label to
Tycho-2. The only exception is the Polar star. This star was due
to it's importance added manually. It is include in original
Tycho-2 but without position and labelled with flag HIP source in
UCAC4 so omitted in the automatic merge.

The star proper motion is not included, but an update with the
correct epoch (currently 2017) will released.

The star labels of both the Tycho-2 and UCAC4 stars, magnitude and
accurate position are preserved in the very compact HNSKY format
of 11 bytes only. See .290 format
description.

Total size of Tycho-2++ is about 46 Mbyte. Up to magnitude 7 it
contains 147 UCAC4 stars and up to magnitude 10 it contains only
336 UCAC4 stars.

Abstract:

The Tycho-2 Catalogue is an astrometric reference catalogue
containing positions and proper motions as well as two-colour
photometric data for the 2.5 million brightest stars in the sky.
The Tycho-2 positions and magnitudes are based on precisely the
same observations as the original Tycho Catalogue (hereafter
Tycho-1; see Cat. <I/239>)) collected by the star mapper
of the ESA Hipparcos satellite, but Tycho-2 is much bigger and
slightly more precise, owing to a more advanced reduction
technique.

Components of double stars with separations down to 0.8 arc sec
are included. Proper motions precise to about 2.5 mas/yr are
given as derived from a comparison with the Astrographic
Catalogue and 143 other ground-based astrometric catalogues, all
reduced to the Hipparcos celestial coordinate system. Tycho-2
supersedes in most applications Tycho-1, as well as the ACT
(Cat. <I/246>) and TRC (Cat. <I/250>) catalogues
based on Tycho-1. Supplement-1 lists stars from the Hipparcos
and Tycho-1 Catalogues which are not in Tycho-2. Supplement-2
lists 1146 Tycho-1 stars which are probably either false or
heavily disturbed.

For more information download the readme files from the web Page
mentioned above.

The magnitude error is larger then for the Tycho catalog. HNSKY
will select the brightest value from "UCAC fit model magnitude",
"UCAC aperture magnitude" and "B magnitude from APASS". The 2MASS
unique star identifier is displayed in the status bar of HNSKY.

Here an example of NGC884 & NGC869 using the UCAC4:

Abstract:

UCAC4 is a compiled, all-sky star catalog covering mainly the 8
to 16 magnitude range in a single bandpass between V and R.
Positional errors are about 15 to 20 mas for stars in the 10 to
14 mag range. Proper motions have been derived for most of the
about 113 million stars utilizing about 140 other star catalogs
with significant epoch difference to the UCAC CCD observations.
These data are supplemented by 2MASS photometric data for about
110 million stars and 5-band (B,V,g,r,i) photometry from the
APASS (AAVSO Photometric All-Sky Survey) for over 50 million
stars. UCAC4 also contains error estimates and various flags.
All bright stars not observed with the astrograph have been
added to UCAC4 from a set of Hipparcos and Tycho-2 stars. Thus
UCAC4 should be complete from the brightest stars to about R=16,
with the source of data indicated in flags. UCAC4 also provides
a link to the original Hipparcos star number with additional
data such as parallax found on a separate data file included in
this release.

The proper motions of bright stars are based on about 140
catalogs, including Hipparcos and Tycho, as well as all catalogs
used for the Tycho-2 proper motion construction. Proper motions
of faint stars are based on re-reductions of early epoch SPM
data (-90 to about -20 deg Dec) and NPM (PMM scans of early
epoch blue plates) for the remainder of the sky. These early
epoch SPM data have also been combined with late epoch SPM data
to arrive at proper motions partly independent from UCAC4
(Girard et al. 2011). The NPM data used in UCAC4 are not
published. No Schmidt plate data is used in UCAC4.

Here an example of NGC884 & NGC869 using the using the NOMAD
online catalog:

Abstract:

The U. S. Naval Observatory is pleased to announce the first
release of the Naval Observatory Merged Astrometric Dataset
(hereafter referred to as NOMAD). NOMAD is a simple merge of
data from the Hipparcos, Tycho-2, UCAC-2 and USNO-B1 catalogues,
supplemented by photometric information from the 2MASS final
release point source catalogue. The primary aim of NOMAD is to
help users retrieve the best currently available astrometric
data for any star in the sky by providing these data in one
place.. The 100 GB dataset contains astrometric and photometric
data for over 1 billion stars.

You have just have just adjusted the date at 2002-7-25, 3:30 UT
and zoomed in to M1. Saturn is eclipsing M1. This event can be
saved as"Eclipse of the Crab nebula by Saturn". To recall this
event, justload this file as an event. The time of the event,
position and zoom factor will be returned.

Save status in the pull down menu "File" will save all your
settings including your position on Earth, equinox, parallax, time
zone, window size and night vision mode. These settings are stored
in the file DEFAULT.HNS. After start-up these settings are loaded
again automatically. Depending on your setting in main menu
"SETTINGS", the program will start with the view at midnight or
actual. The save/load option behaviour is different for high and
low magnifications or zoom factors. For high zoom factors, the
program will return the same RA/DEC as saved. Due to time
differences, the view will be slightly rotated, unless load event
to restore original time and date is used. For low zoom factors,
the program will always return the same Azimuth/Altitude as saved.
This is good for start-up overviews such as a wide view to the
south.

Save as The program settings are saved in a different file
then DEFAULT.HNS. "Save as" is a helpful tool to find and restore
your favourite object.

Load status The saved status is restored. This will not
(unless your load DEFAULT.HNS) effect your settings for position
on Earth, equinox, parallax, time zone, window size and night
vision mode and time settings)

Load event As load status but also the original time and
date are restored.

Setting and event files in ASCII
format.you can load/save. During start-up 'default.hns is
loaded'

Located in: Documents\hnsky\fits

*.fit

Several deep sky and planetary images in
FITS format.

Located in: Documents\hnsky\cache

*.txt

Cache of online downloaded star
catalogues UCAC4, NOMAD.

The above files locations are for v3.0.1 and higher
The Windows hidden "Application Data" directory is not used by
purpose.

New fresh installations of the program will by default be placed
in the "c:\Program Files\hnsky" directory. Existing installations
will stay in the previous selected directory such as "c:\hnsky".
If you want to move the new location, then save your default.hns
settings file somewhere else, uninstall the old version, install
the new version and copy & overwrite the default.hns file.

UCAC4 (local & online) and NOMAD are the only databases which
will provide star proper motion..

The online FITS files and UCAC4, NOMAD star cache files are placed
in the FITS directory. The star cache files can be cleared form
the FILE menu, "Delete online cache", however the will not slow
down the program in any way. The online downloaded FITS files can
be deleted from the pop-up menu.

Selection of deep sky databases: The different databases can be
selected in the "OBJECT menu". For
beginners it is advisable to select the small deep sky database
HNS_SAC1.DAT which contains 265 easy and/or interesting objects
including all Messier deep sky objects. For all these object,
there are FITS images available which will blend automatically in
the map if required.

HNSKY is available in several languages. The translated text is
stored in one INI file. To select an other language INI file go to
FILE menu, sub menu SETTINGS
(CTRL+E) and select the desired language file.

With any text editor, you could create a new language module for
HNSKY. If your native language is missing, your are invited to
create a new language module. Download the English module from The HNSKY web page, translate it and send it back to
me.

Help file:

Available in English, Spanish and Catalan. Some obsolete
translations are still available: Italian, Romanian, Korean,
Volunteers to update or create new translations are welcome.

All labels should be there. Removing them will result in blank
menu items.

You could enter keys such as W or CTRL+W or Alt+W or CTRL+Alt+W.
Single letters such a W (except F1, F2 ...) are not recommended,
since they will block typing in the SEARCH menu.

To disable these files, delete or remove the *.ini file(s). The
original English text and menu short cuts will return. You could
also delete the settings file "default.hns" but you will loose all
you settings including you position.

General remark: HNSKY has a high accuracy. To get comparable and
correct ephemerides it is important to set:

1) Geographical position on Earth correct.
2) Time zone and day light savings. When
necessary check the UTC time in the pull down menu "ABOUT". To get
maximum moon and Sun accuracy, select ΔT correction on.
3) Desired equinox. Normally J2000.
4) Correction for parallax error on for
topocentric values and off for geocentric values.

All positions of the Deep sky and planetary objects are
astrometric referred to equinox J2000 (2000, January 1.5),
equinox B1950, the mean equinox of the current
date or apparent. These are the co-ordinates as they would
appear to a stationary observer at the year 2000, 1950 or current
date. Star positions in J2000 or B1950 may be
compared directly with planet positions. The mean position is
depending on the orientation of the earth of that epoch. The apparent
position are the mean positions corrected for the velocity
of the moving Earth aberration and wobble
of the earth axis nutation. These
aberration and nutations are effecting both stellar and planet
positions equally (max. 30 arc seconds) and does no effect the
displayed map.

The desired equinox can be selected via main menu "FILE" and then
menu option "SETTINGS".

Date and time setting:

Enter the required date and time in the "set time" menu. The day
of the month can be entered with fraction. So entering 30.5 will
give day 30 at 12 noon.
It follows the astronomical year numbering including year 0.
Historians did not use the Latin zero, nulla, as a year, so the
year preceding AD 1 is 1 BC. So year -44 is "45 BC"

The build in monthly calendar doesn't allow a date beyond 1752 and
9999 so a parallel input is created.

Alternatively you could enter the date as Julian day in the JD
tab.

Valid dates of the program :

The program has an internal analytical planetary solution which is
accurate for dates between the year 1750 and 2250, except for
Pluto, which is only accurate between 1890 and 2100. For a longer
period or higher accuracy download the JPL
Propulsion Laboratory Development Ephemeris DE430 or DE431.
The DE431 covers the years -13000 up to 16999.

The internal analytical planetary solution is based on "Astronomy
on the Personal Computer" by O. Montenbruck and T. Pfleger, 1998,
English edition (Almost equal to 1993 edition). This is a very
detailed book for Pascal programmers and contains several
professionally written routines. The source code is on an attached
disk. This book is not intended to be a teaching guide.

Ephemerides calculations for the moons of Mars, Jupiter, Saturn
Uranus, and Neptune are based on their rotation period and their
correct axis orientation (Theta) in space. Their rotation center
position equals the planet position is known from the planet
ephemerides. A basic X,Y,Z calculation is required to determine
their final position in space. Their orbit is calculated as
perfect circular, which is for the major moons more or less
correct. Only for the Moons of Jupiter a correction for their
gravitational interactions factors is made based on some factors
found in the book of Meeus, Astronomical Algorithms edition 1991.

Accuracy of Planet and Moon ephemerides:

The internal ephemerides of the planets have a typical error of a
few arc seconds with a maximum of about ten arc seconds. Only
Neptune has a maximum error of about 40 arc seconds.

The internal ephemerides of the Moon are correct within about one
arc second. It is important to select "ΔT correction" on to get
accurate Moon eclipses. The resulting eclipse is correct within
one maybe two minutes. The JPL Propulsion Laboratory Development
Ephemeris should be spot on.

Rise and set time should be correct within, perhaps, two minutes.
To get accurate rise and set times, the atmospheric refraction
correction should be set "ON" (menu "SET EQUINOX AND LOCATION").
Light from objects close to the horizon is bent while passing
through the atmosphere. Objects close to the horizon will appear
to be higher then their actual position. At zenith, this effect is
zero and increases towards the horizon. At an altitude of 45
degrees it is only 1 arc-minute. At an altitude of 10 degrees it
is 5 arc-minutes and at the horizon it increases rapidly to about
35 arc-minutes.

Note that the rise and set time are given for a date. So if the
HNSKY time is at 2015-11-25 24:00 hours and the rise time is give
as 00:05 hours it happens in the morning at 2015-11-25 00:05 hours
and most likely for you in the past. Is the HNSKY time at
2015-11-26 00:00 hours, rise and set times are given for date
2015-11-26.

Moon ephemerides reference: In general, the positions of the moons
of Mars, Jupiter, Saturn, Uranus and Neptune are displayed with an
error of 10 arc seconds or less. As a reference the ephemeris
values of the 'Bureau of Longitudes' in France, web address and the "Solar System Dynamics
Group of JPL", web address were used.

Remarks:

- The parallax error can be corrected. To get the geocentric value
instead of the topocentric value, switch correction for parallax
"OFF".
- Error due to speed of light, velocity of planets is corrected.
- Rise and set time. They are all, except for the Sun and Moon,
given for the center of the object. For the Sun and Moon it is
given for the upper limb of the disk.

Accuracy of the star database:

Star motion (proper motion) is not implemented except for the USNO
UCAC4 and online NOMAD.
The HNSKY version of the SAO database does not contain star
motion. Star position is correct for Equinox and Epoch 2000. For
any other date only the Equinox can (if selected) be recalculated
to the equinox of the current date or 1950. This means that in the
several decades, before and after the year 2000, the positions of
a few stars will have small errors. These (nearby) stars will move
slowly across the sky introducing an error in arc seconds. If this
program is still in use after 50 years, an updated star database
could be created.

In addition to above, the star motion data is in the GSC database
is not available. This catalog is based photographic plates made
in 1978 and has therefore an epoch of around 1978 and positions
are given in equinox J2000.

In the main menu "SCREEN" there are four tools to measure and aim
objects:
1) Cross-hair. Automatic adjusted circles for quick estimate of
distances. The numbers in the cross-hair indicate the distance
from the center (radius !!) of the cross-hair in degrees. The
numbers are in line to the north.

2) Imaging sensor measuring frame. At the mouse cursor a rectangle
box will be shown, default orientated North/South. The
orientation can set with the mouse wheel while holding the CTRL
key. The size of the frame is defined under "FILE",
"SETTINGS". This frame will help you to determine which part of
the sky is visible on your sensor or your photographic film. Use
Ctrl & mouse scroll wheel to rotate the measuring
frame.

3) If the measuring frame is ON, you can draw rectangles by
pressing the HOME button. The J2000 or MEAN position is given and
orientation. The rectangles can be removed by pressing CTRL+DEL
(as defined in the markers and line menu) The
rectangles are stored a 4 lines in supplement 2. Save supplement 2
to make is permanent. See next image.

4) Pointing device. This can be used as a simulation of an aiming
device such as TelRad. It shows maximum 5 fixed size circles.
These aiming devices such as Telrad consists of a glass plate
through which you look at the sky, which project's three
concentric red circles (typical 4, 2, and 0.5 degrees)
"superimposed" on the sky. You simply move the telescope while
looking at the sky through the Telrad finder until the circles are
centred on the desired object.

5) Zoom box. While keeping left mouse button down and pulling with
the mouse a zoom square, the distance and angle are give in the
status bar. Make zoom box small afterwards to prevent zooming in
or use CTRL+Z to return to previous view.

Next a design
for a M31 mosaic using for four image fields at an angle of 50
degrees. The angle of the measuring frame is adjustable with the
mouse wheel while holding CTRL down. The position is referring
to the center of the frames.

Found object markers

As soon an object is found in the database it can be marked in
three ways as set in main menu 'SCREEN', sub menu 'FOUND OBJECT
MARKER':

1) Two short lines orientated North-South.
2) Pointing circle marker. This is very
handy to make a field map with several of these circles.
3) Name of object marker.
4) Magnitude of object marker.

Then there is the special possibility to copy the object info into
the clipboard so it can be passed into other Windows applications.

Functionality: HNSKY can add deep sky images to the sky
map. You can download them directly from the internet using the pop-up menu. This is the easiest and simplest
method. You could add your own images. These images should be in
the FITS format with the extension *.FIT *.FITS or *.FIT*. Each
image should contain information about its position and pixel size
and orientation in the so-called WCS format. HNSKY will read all
FITS file as available and if required, plot them with the right
size and orientation.

Images without the WCS keywords can't be used, unless you add them
using a plate solver e.g. the online solver http://nova.astrometry.net/
or the HNS_FV
program &Platesolve2. For more information see below
"compatibility".

Filtering: The directory where
HNSKY will look for FITS files can be set in SETTINGS. It will
read all available 8, 16 bit or -32 float FITS files. If you have
more then a few hundred FITS files, a file mask or filter could
speed up the loading. Examples: 23*45*.FIT* or *_ORI.FIT*.

Image color: The color of the images is default red but can
be set in one of the basic RGB colors in the menu SETTINGS, sub
menu COLORS. The program supports also color FITS files but only
in the format described below. Most color FITS images contain the
three colors separate. You will need the program HNS_FV to create
these files.

Background, Brightness: The FITS background and brightness
are adjustable with the two sliders at the bottom of the OBJECT
menu. Some deep sky DSS pictures are under-overexposed and need
some fine-tuning to get maximum detail.

The first pixel in the DSS gets a hint containing the FITS file
name and size. Normally that is the south-east corner.

Printing: Best printing results are obtained with a color
printer. A black and white laser printer give less satisfactory
results while the gray simulation spoils small details. In some
cases a fixed map orientation to the North could improve plotting
since the pixels are plotted as squares.

Compatibility: FITS images are very popular in astronomy
and can contain all kinds of information but in our case just an
image. The FITS (Flexible Image Transport System) files start with
a pretty long information header, which in our cases should
contain the image size, position and orientation in a subset of
the so called WCS (World Coordinate System) format.

Almost all DSS images contain in the header 2x20 DSS polynomial
factors to calculate the pixel position with a high accuracy.
These polynomials compensate for optical or plate non-linearities.
These factors are not used in HNSKY.

Color FITS files can come in two types. They are using a third
dimension for the RGB color information. HNSKY supports only the
type where BITPIX=8 and NAXIS1=3 and does not support NAXIS3=3.

They are drawn proportional around Jupiter and Saturn. To see them,
a high zoom factor is required. (use Pgup/Pgdown or auto zoom option
in search menu). At these magnifications you will need solar tracking otherwise as soon the time is
changed it will move out of sight..

Change the time by using the buttons F3, F4, F5 and F6. The moons
will also start to rotate their planets. The planet's position will
change due to its own motion through the sky.

The program is very suitable to observe and study solar and lunar
eclipses. A solar eclipse occurs when the Earth slips in the shadow
of the Moon. Only a very small part of the Earth surface will become
fully dark. A lunar eclipse occurs when the Moon slips in the shadow
of the Earth. While the Earth is much bigger then the Moon, also
it's shadow is much larger. The complete Moon can slip inside the
Earth shadow. A lunar eclipse is visible from anywhere on the night
side of the Earth.

Lunar eclipse in HNSKY: As soon the phase of the Moon reaches 99.8
%, the two shadow boarders (umbra and penumbra) are drawn by the
HNSKY program. The inner circle (umbra) is where the Sun light is
fully blocked by the Earth. In practice still a small part of the
Sunlight is scattered through the Earth's atmosphere inside the
umbra and the Moon will get a dark reddish color. The outer circle
(Penumbra) indicates where the Sunlight is partial blocked by the
Earth. Observers will see only the slightest dimming. Unless at
least half of the Moon enters the penumbra, the eclipse may be
undetectable !

The animation menu allows to find the lunar
and solar eclipses for your location as set.

For FPC versions of the program
only. These commands are for communication with astro
photography tools as APT & CCDciel
(near future).

HNSKY server commands and
responses.

For HNSKY FPC
version only.

Default port number is 7700

Program will accept both dot and comma as
decimal separator. Will send numbers with decimal
separator as set in the operating system.
All positions and sizes in radians. Positions in equinox
J2000.

Requests to planetarium program

Response

Remarks

SET_FRAME width height angle ra dec (label)

OK

Frame is stored in supplement 2. Label is
optional Save supplement 2 will make it permanent.

ADD_FRAME width
height angle ra dec (label)

OK

Every time a new frame is added to
supplement 2

SET_POSRA DEC
(field_height)

OK

Center
map on position give. Field height is optional.

LOAD FITS
file_name

OK

Load
a FITS file in the map with the correct size and
orientation.

GET_POS

RA DEC

Return
position of map center.

GET_TARGET

RA DEC object_name (frame_PA)

Returns last found object or exported position. The
frame_PA is send if the sensor measuring frame is
activated.

SEARCH
object_name

RA DEC object_name

This
command will work for deep sky, stars and planetary
objects. Select the required deep sky database level in
HNSKY first, level 1,2,3 . Response will be three fields
with space as separator.

SHUTDOWN

Shutdown the planetarium program.

HELP

Brief description of the commands

?

Command
not understood.

Info
from planetarium program

Response

Remarks

RA DEC
object_name (frame_PA)

Planetarium program sends unsolicited an
object position after an object is found or
when "export position" is selected in the mouse
pop-up menu. The frame_PA is send if the sensor measuring
frame is activated.

Aberration: An effect caused by the Earth's motion, which
slightly changes the positions of stars. They tend to move to the
same direction as the moving earth. This effect would be very
visible if the earth moves close to the speed of light. However it
moves much slower and the effect is in one direction only 20 arc
seconds maximum. It will effect equally all objects in one
direction and is for mapping purposes irrelevant.

Asteroid: A small, rocky body that moves in an elliptical
orbit around the Sun. They are too small to have atmospheres. Also
called minor planet.

Arc minutes and seconds: One complete circle has 360
degrees. There are 60 minutes (denoted as 60') of arc in 1 degree.
There are 60 seconds (denoted 60") of arc in one minute of arc.

Astronomical Unit (AU): Approximately equal to the mean
Earth-Sun distance, which is 150 000 000 km or 93,000,000 miles.
Formally, the AU is actually slightly less then the Earth's mean
distance from the Sun (semi-major axis) because it is the radius
of a circular orbit of negligible mass (and unperturbed by other
planets) that revolves about the Sun in a specific period of time.
(1 AU = 149 597 870.66 km)

Cartesian co-ordinates: (Astronomical) co-ordinate system
where the position of an object is given in rectangular X, Y and Z
values. This system is often used inside programs.

Comet: Icy body embedded in a cloud of gas, which orbits
around the Sun. When they orbit close to the Sun they heat up,
releasing gas, which appears as a tail always pointing away from
the Sun. In principle an icy minor planet.

DEC, Declination: One element of the astronomical
co-ordinate system on the sky that is used by astronomers.
Declination, which can be thought of as latitude on the Earth
projected onto the sky, is usually denoted by the lower-case Greek
letter δ = delta and is measured north (+) and south (-) of the
celestial equator in degrees, minutes, and seconds of arc. The
celestial equator is defined as being at declination zero (0)
degrees; the north and south celestial poles are defined as being
at +90 and -90 degrees, respectively.

Dynamical time, DT or Terrestrial Time (TT): A uniform
measure of time, which is used to calculate solar objects. It was
introduced to be independent of unpredictable variations of the
Earth's rotation which forms the basis of Universal Time, UT. The
difference between DT and UT was around the year 1900 set at zero
and is now almost one minute. See also UTC and Wikipedia
TT

Ephemeris (plural: ephemerides): A table listing specific
data of a moving object, as a function of time. Ephemerides
usually contain right ascension and declination, apparent angle of
elongation from the Sun (in degrees), and magnitude (brightness)
of the object; other quantities frequently included in ephemerides
include the objects distances from the Sun and Earth (in AU),
phase angle, and moon phase.

Epoch: Point of time selected as a reference, especially
for stellar positions and orbital elements. A photographic plate
made in 1978 is a reference of star positions with epoch 1978 as
well equinox 1978. While the drifting of the co-ordinates of the
sky due to changes in the Earth's rotational axis is known their
position could be calculated for 2000 or equinox 2000 is they do
not move. This calculation will result in equinox 2000, epoch
1978. If their motion is known, also their epoch could be
recalculated for 2000.

Equinox: the
fundamental plane of an astronomical reference system has
conventionally been the extension of the Earth's equatorial
plane, at some date, to infinity. The declination of a
star or other object is its angular distance north or south of
this plane. The right ascension of an object is its
angular distance measured eastward along the equator from some
defined reference point where the right ascension value is set
to zero. This reference point, the origin of right ascension,
has traditionally been the equinox: the point at which
the Sun, in its yearly circuit of the celestial sphere, crosses
the equatorial plane moving from south to north. The Sun's
apparent yearly motion lies in the ecliptic, the plane
of the Earth's orbit. The equinox, therefore, is a direction in
space along the nodal line defined by the intersection of the
ecliptic and equatorial planes; equivalently, on the celestial
sphere, the equinox is at one of the two intersections of the
great circles representing these planes. Because both of these
planes are moving, the coordinate systems that they define must
have a date associated with them; such a reference system must
be therefore specified as "the equator and equinox of [some
date]". The equinox is therefore at position RA=0, DEC=0.
While the earth axis
and equator is slowly drifting, the reference of the celestial
equator and celestial poles is changing with respect to the
stationary stars. referencehttp://aa.usno.navy.mil/faq/docs/ICRS_doc.php

J2000:celestial coordinate system adapted to
the mean earth pole and
mean equator on 2000 Jan.
1.5 TD or 2000 Jan. 1 12:00 hours dynamical time or Julian
date 2451545.0. It was fixed to the stars by the FK5
definition but now by its successor ICRS and based on set of distant
extragalactic objects". The ICRS axes are consistent, to
better than 0.1 arcsecond, with the equator and equinox of
J2000.0 defined by the dynamics of the Earth. However, the ICRS
axes are meant to be regarded as fixed directions in space that
have an existence independent of the dynamics of the Earth or
the particular set of objects used to define them at any given
time. Modern positions are given in ICRS

Mean
equinox of date, coordinate system based on Earth mean pole and equator at the
current date.

Apparent
coordinates, as mean equinox of date but
corrected for the
velocity of the moving Earth aberration
and wobble of the earth axis nutation.
These
aberration and nutations are effecting both stellar
and planet positions equally (max. 30 arc seconds) and
does no effect the displayed map.

Geocentric: Co-ordinates referred to the center of the
Earth. (Position in the sky as seen from the center of the Earth.

Heliocentric: Co-ordinates referred to the center of the
Sun.

Julian date (JD): The interval of time in days (and
fraction of a day) since Greenwich noon on Jan. 1, 4713 BC. The JD
is always half a day off from Universal Time. (In the past an
astronomical day in Europe was defined to start at noon instead of
midnight.) A Julian year is exactly 365.25 days in which a century
(100 years) is exactly 36,525 days and in which 1900.0 corresponds
exactly to 1900 January 0.5. This JD system is frequently used in
astronomy. This way of time counting gives a continuous series of
days and decimals of day, unbroken by subdivisions in months and
(leap) years.

Mean anomaly: See explanation orbital elements.

Minor planet: See asteroid.

Nutation: Is a small wobble of the earth axis with a 18.6
year orbit. This effect influences the position with a maximum of
17 arc-seconds and has the same effect for all objects. The
nutation of planetary objects is corrected to get their correct
equinox 2000 position. So stellar and non-stellar objects
positions will be relatively correct.

Orbital elements: Parameters (numbers) that determine an
object's location and motion in its orbit about another object. In
the case of solar-system objects such as comets and planets, one
must ultimately account for perturbing gravitational effects of
numerous other planets in the solar system (not merely the Sun).
When such an account is made, one has what are called "osculating
elements" (which are always changing with time and therefore must
have a stated epoch of validity). Six elements are usually used to
determine, uniquely, the orbit of an object in orbit about the
Sun, with a seventh element (the epoch, or time, for which the
elements are valid) added when planetary perturbations are allowed
for; initial ("preliminary") orbit determinations shortly after
the discovery of a new comet or minor planet (when very few
observations are available) are usually "two-body determinations",
meaning that only the object and the Sun are taken into account
with, of course, the Earth in terms of observing perspective) work
with only the following six orbital elements: time of perihelion
passage (T) [sometimes taken instead as an angular measure called
"mean anomaly", M]; perihelion distance (q), usually given in AU;
eccentricity (e) of the orbit; and three angles (for which the
mean equinox must be specified) the argument of perihelion
(lower-case Greek letter omega), the longitude of the ascending
node (upper-case Greek letter Omega), and the inclination (i) of
the orbit with respect to the ecliptic.

Parallax error: Error due to the geographical position on
Earth. Mainly affecting the position of the Moon in the sky. Due
to the great distances of the planets only a small error occurs,
mainly in the position of our neighbours Mars and Venus.

Perihelion: The point where (and when) an object orbiting
the Sun is closest to the Sun.

Perturbations: Disturbances of planet motion due to the
gravitational forces between the planets.

Polar co-ordinates: Astronomical co-ordinate system on the
sky, which can be thought of as longitude/latitude on the Earth
projected onto the sky. The two co-ordinates are right ascension
and declination

Precession: A slow but, relatively uniform motion of the
Earth's rotational axis that causes changes in the co-ordinate
systems used for mapping the sky. The Earth's axis of rotation
does not always point in the same direction, due to gravitational
tugs by the Sun and Moon (known as lunisolar precession) and by
the major planets. This leads to a long-term shift of the ecliptic
and the celestial equator. Commonly, to get a standard epoch, the
co-ordinates are referred to as the equinox of data. This was
before 1984 Besselian year B1950 = 1950, Jan. 0,9235 or Julian
date 2433282.4235. Now the Julian epoch J2000 = 2000 Jan. 1.5 TD
or 2000 Jan. 1 12:00 hours dynamical time or Julian date
2451545.0. The dynamical time (before 1984 emphemeris time) is in
1998 about 64 seconds ahead of universal time (UT).

RA: Right ascension, one element of the astronomical
co-ordinate system on the sky, which can be thought of as
longitude on the Earth projected onto the sky. Right ascension is
usually denoted by the lower-case Greek letter a=alpha and is
measured eastward in hours, minutes, and seconds of time from the
vernal equinox. There are 24 hours of right ascension, though the
24-hour line is always taken as 0 hours.

Sidereal time: Is the hour angle of the vernal equinox, the
ascending node of the ecliptic on the celestial equator. The daily
motion of this point provides a measure of the rotation of the
Earth with respect to the stars, rather then the Sun. Local mean
sidereal time is computed from the current Greenwich Mean Sidereal
Time plus an input offset in longitude (converted to a sidereal
offset by the ratio 1.00273790935 of the mean solar day to the
mean sidereal day.) Applying the equation of equinoxes, or
nutation of the mean pole of the Earth from mean to true position,
yields local apparent sidereal time. Astronomers use local
sidereal time because it corresponds to the coordinate right
ascension of a celestial body that is presently on the local
meridian.

Topocentric: Position in the sky as seen from the observers
place on Earth. Topocentric co-ordinates differ from geocentric by
the amount of parallax.

Vernal equinox: The point on the celestial sphere where the
Sun crosses the celestial equator moving northward, which
corresponds to the beginning of spring in the northern hemisphere
and the beginning of autumn in the southern hemisphere (in the
third week of March). This point corresponds to zero (0) hours of
right ascension.

UT: Universal Time. A non-uniform of time which is the best
realisation of solar time. The length of one second of Universal
Time is not constant because the actual mean length depends on the
rotation of the Earth and the apparent motion of the Sun. It is
not possible to give long-term predictions. The difference between
UT and DT are published in various yearbooks. See Wikipedia delta T

UTC: Co-ordinated Universal Time. Our clock time based on
atomic clocks which are adjusted once or twice a year with leap
seconds to be close (0.9 seconds or less) to Universal Time, UT.
UT is based on rotation of the Earth.

The emphemeris time, ET, since 1984, the DT (TDT, Terrestrial
Dynamical Time and TDB, Barycentric Dynamical Time), is the basis
of the table for motion of the Sun, Moon, and planets without the
influence of changes in the rotation of the Earth. Ephemeris of
the planets is calculated on basis of this dynamic time. UT is
based on solar time and therefore on the rotation of the Earth.
This is leading to a small difference between DT and UT or
Universal time. Secondly, there is a tiny difference between UT
and UTC but, within one second. See also glossary.

ΔT is now based on the TAI International Atomic Time.

To get correct Moon (about 30 arc seconds) and Sun ephemerides
this small difference between our UTC based PC clock and DT should
be corrected. HNSKY has an internal DT-UT table valid between
-13000 and 17000. This feature ΔT correction
can be switched off and the time can be entered as DT or the ΔT correction
can be included in the time zone value. The ΔT difference
in 2000 is about 64 seconds. To correct this, the difference
should be subtracted from the time zone. E.g. in the Netherlands
for the time zone a value of 0.982 should be entered instead of
+1.0. For East-USA a value of -5.018 instead of -5.0 should be
entered. Here is a small table with the ΔT differences
of the past 300 years :

For comets normally the perihelion passage time (T0)
and the perihelion distance (q) is given. The orbital elements of
asteroids are given for one given instant, called EPOCH and the
MEAN ANOMALY. To convert these elements to the orbital elements
(T) and (q) typically used for comets, the following simple
calculations could be used:

The HNSKY deep sky database is based on the SAC
8.1 , Wolfgang Steinicke's REV
NGC&IC, Leda (GX), Kent Wallace SEC (PN) database, a few other
sources and some personal corrections using the DSS2. It should
contain all existing objects to magnitude 15.5 and galaxies if
larger the 1 arc-min. It contains most of the NGC,
and IC including all Messier objects. A total of 30000 deep
sky objects. The deep sky databases are stored in a simple text
file in CSV format and sorted on magnitude. Each line contains one
object and the data is separated by a comma. This format is
designed for speed and should normally not be modified by the
users. To add your own object use the flexible but slower supplements. The visual descriptions of
most deep sky objects are given, see abbreviations.
The databases has three levels. The level can be set in main menu
"OBJECTS".

These flexible database supplements can be used by users to enter
additional deep sky objects, stars, labels and local horizons.
Sorting on magnitude is not required. By using the internal HNSKY
editor you can check the syntax. Due to the format, the speed is
lower then for the standard deep sky database. HNSKY can become
slow when the number of objects is above 10000. File names
HNS_****.SUP. The format is defined in the first comment lines of
the provided samples and in supplement files or here. Lines starting with ; are
interpreted as comments. For creating a new large supplement a
spreadsheet could be handy. The result should be saved as *.csv
format.

3) Asteroid database

CSV input file for asteroids. By using the internal HNSKY editor
you can check the syntax. File name HNS_AST1.AST. The format is
defined in the first comment lines of the provided samples and here. Lines starting with ; are
interpreted as comments.

4) Comet database

CSV input file for orbital element of comets. By using the
internal HNSKY editor you can check the syntax. File name
HNS_COM1.CMT. The format is defined in the first comment lines of
the provided samples and here. Lines
starting with ; are interpreted as comments.

5) Format of the .290 star database.

The .290 format divides the sky in 290 area's and 290
corresponding files with the extension .290. It is intended for
larger star databases.

The 290 format: Each star is stored in a record of 5 , 6 ,
7 or 9, 10, 11 bytes. All types have the same 110 byte header with
textual description and the record size binary stored in byte 110.
The short record versions of 5, 6 and 7 bytes have no star
designation and get later the IAU designation based on the
recorded RA, DEC position as hhmmss.s+ddmmss

Basic record formats:

290-11, standard record size of 11 bytes for one star
including it's designation:

The RA is stored as a 3 bytes word. The DEC position is stored as
a two's complement (=standard), three bytes integer. The
resolution of this three byte storage will be for RA:
360*60*60/((256*256*256)-1) = 0.077 arc seconds. For the DEC value
it will be: 90*60*60/((128*256*256)-1) = 0.039 arc seconds. The
magnitude is stored in one short-integer. Used range -127 to 127,
equal -12,7 to 12,7. Stars with a magnitude 12.8 and higher are
stored as -12.6 and lower.

290-10 and 290-6 versions. Since the stars are sorted from
bright to faint, a "0.1" magnitude change of a sorted group can be
stored in one preceding header record containing a dummy RA
position 24:00:00 ( $FFFFFF) and the magnitude in the dec9
shortint with range -127 to 127. The stars following the header
record do not need a magnitude byte/shortint. Stars with a
magnitude of 12.8 and higher are stored as -12.6 and lower.

290-9 and 290-5 versions. These are the latest and most
compact star database versions. Stars are sorted from bright to
faint in the "0.1" steps. Within the magitude range, the stars are
additional sorted in DEC. For a series of stars with the same DEC9
value, a header record is preceding containing the DEC9 value
stored at location DEC7. Since the stars are already sorted in 290
areas, the number of DEC9 values is already limited by a factor
18.

The shorter records methods become only space efficient for very
large star collection of a few million stars. In these large
collections many stars can be found with the same magnitude and
DEC9 shortint. The Gaia database is only issued in the 290-5
format of 5 bytes per star.

Designation: The star designation is stored in 32 bit
integer named NR290. If the NR290 integer is positive, it contains
an UCAC4 number. For UCAC4 the star zone is added as a multiply of
$100000. This allows $800 or 2048 zones and $100000 or
1.048.576 stars. The UCAC4 contains maximum 286.833 stars in a
zone and has 900 zones.

In case the NR290 integer is negative, the integer contains the
Tycho/GSC label. After making the integer positive, the regional
star number is stored in the lowest 2 bytes, the GSC/Tycho star
region (1..9537) is stored in the highest 2 bytes except that if
bit $40000000 is true, the Tycho specific extension is 2, else the
Tycho extension is 1. The highest bit of star number at $00008000
is used for the Tycho-2 extension 3.

if (((-nr32store) and
$40008000)>0) then {tycho extensions}
begin
if (((-nr32store) and
$40000000)>0) then
naam2:=naam2+'-2'
else
naam2:=naam2+'-3';
end;

The sky is divided in 290 areas of equal surface except for the
poles which are half of that size. The stars are stored in these
290 separate files and sorted from bright to faint. Each file
starts with a header of 110 bytes of which the first part contains
a textual description and the last byte contains the record size,
6, 7, 10 or 11 bytes. The source of the utility program to make
star databases is provided.

The 290 area's look as follows:

The 290 area's:

The areas are based on an mathematical method described in a paper
of the PHILLIPS LABORATORY called "THE DIVISION OF A CIRCLE OR
SPHERICAL SURFACE INTO EQUAL-AREA CELLS OR PIXELS" by Irving I.
Gringorten Penelope J. Yepez on 30 June 1992

First circles of constant declination are assumed. The first
sphere segment defined by circle with number 1 has a height h1
from the pole and a surface of 2*pi*h1.

If the second circle of constant declination has a sphere segment
with a height of 9*h1 then the surface area of the second sphere
segment is nine times higher equal 2*pi*9*h1. If the area between
circle 1 en 2 is divided in 8 segments then these eight have the
same area as the area of the first segment. The same is possible
for the third circle by diving it in 16 segments, then in 24, 32,
40, 48, 56, 64 segments. The area of the third segment is
2*pi*25*h1, where 25 equals 1+8+16. So the sphere segments have a
height of h1, 9*h1, 25*h1, 49*h1. The height of
h1=1-sin(declination). All areas are equal area but rectangle. In
HNSKY all area's are a combination of two except for the polar
areas to have a more square shape especially around the equator.
The south pole is stored in file 0101.290 Area A2 and A3 are
stored in file 02_01.290, area A4 and A5 are stored in file
0202.290. The distances between the circles is pretty constant and
around 10 to 12 degrees. The distance between the area centres is
around 15 degrees maximum.

The internal HNSKY
star databases comes in two binary formats. The .290 format
and a single file type with extension .dat This type is intended
for databases up to about a half million stars. File names
***_HSKY.DAT. In this format the spectral
code is is available. Examples, The SAO (sao_hnsky.dat) up to to
about magnitude 9.5 and the PPM (ppm_hnsky.dat) star database
complete to about magnitude 10.

The record size for one star is then 11 bytes. Stars in the files
are sorted from bright to faint.

The SAO/PPM number is stored in three bytes. Range 0 to 256^3-1.
The RA position is stored in three bytes. Range 0 to 256^3-1,
equals 0 to 2*pi or 24 hours. The DEC is stored as a three bytes
integer (two's complement), so one bit is used for the polarity
sign. Used range - 128*256*256-1 to +128*256*256-1, equals -pi/2
to pi/2 or -90 to 90 degrees

The resolution of this three byte storage will be for RA:
360*60*60/((256*256*256)-1) = 0.077 arc seconds. For the DEC value
it will be: 90*60*60/((128*256*256)-1) = 0.039 arc seconds

The magnitude is stored in one byte or shortint, Used range -127
to 127, equal -12,7 to 12,7. Stars with a magnitude 12.8 and
higher are stored as -12.6 and lower.

The first 10 records+1 (111 bytes) are not used for star data, but
contain a file description in txt/ASCII. The stars are sorted from
bright to faint.

The size of the database is in principle unlimited, but a bigger
database will slow down the build-up of the display. The program
reads the database from disk and after some calculations the data
is written directly to the window. Therefore the memory
requirements of the program are very low.

Star proper motion is not implemented. Epoch is corrected by
issuing every few years a new version with a proper epoch.

So DEC is stored as a two's complement (=standard), three bytes
integer. The algebraic value of the two's complement can be found
of the summing weight of sign bit (+ or - 256*256*128 ) and other
bits added positively only.

Back to the indexSupplements for deep sky
objects, stars, lines, logbook and local horizon.

These flexible database supplements can be used by users to enter
additional deep sky objects, stars, labels and local horizons.
Sorting on magnitude is not required. By using the internal HNSKY
editor you can check the syntax. Due to the format, the speed is
lower then for the standard deep sky database. HNSKY can become
slow when the number of objects is above 10000. File names
HNS_****.SUP. The format is defined in the first comment lines of
the provided samples and in supplement files. Lines starting with
; are interpreted as comments. For creating a new large supplement
a spreadsheet could be handy. The result should be saved as *.csv
format.

HNSKY can handle two supplements. They can contain a mixture of
deep sky objects, stars, constellation lines, local horizon and logbook markers. Supplements are ordinary
TXT files and can be modified inside HNSKY or any other editor.
There are several examples available at the
HNSKY webpage. A deep sky object could be entered as
following line:

02,22.5,0,+42,21,0,101,NGC891,GX;old_position,131,120,20,22

The position of the galaxy NGC891 is at RA 02:22.5 and DEC +42 d
21. The magnitude is 10.1 and brightness is 13.1. The size is 12.0
x 2.0 arc minutes. The PA angle 22 degrees.

Under the editor tools menu there are two options to import a list
of objects as a supplement. Copy a piece of text containing
deep sky names (e.g. webpage) and paste it. Any recognisable
object name will be filtered out and object info from the HNSKY
database will be added. It can be pasted as a label or
supplement line. Since HNSKY completes the data it is advisable to
select first the deep sky database 3.

Deep sky mode:
As soon the brightness value is given, (if unknown
enter 999) the entry will
be displayed as a deep sky object.

Star mode:
As soon brightness=0 or a text description is given
or nothing at brightness
field the entry will be displayed as a star. The
brightness field can be used for
additional information. If the brightness text is
too long, split it with
the symbols ; or / or |. If the object is found,
this the full text will be
displayed in the status bar, however only the first
part will be displayed in
the screen top&left message.

Line mode:
1) RA/DEC To draw RA, DEC lines enter
brightness=-2 to move to and -1 to draw
line
to.
The line color is defined by the magnitude see below.
To
enter
a RA, DEC based label, enter brightness=-99. This will also
disable
the
hint. if the RA, DEC based label requires an hints enter
brightness=-98.

2) AZ/ALT To draw azimuth, altitude lines
enter brightness=-4 to move to and
-3
to draw line to.
The
line
color is defined by the magnitude. See below.
To
draw
circles in azimuth, altitude enter brightness=-5
To
get
a azimuth/altitude based label+hint enter the name.

In the RA/DEC or AZ/ALT line mode the color
can be set by the magnitude parameter.
mag value -20 is the horizon color, -21 is
bright deep sky, -22 medium, -23 faint,
-24 is constellation boundary color, -25 is
cross_hair and finally else
(mag=0 or empty) constellation color.

All numbers are read as floating point. So RA of 23:30:00 could
be entered as
23,30,0 or as 23.5,0,0 or as 0,1410,0 (RA minutes is
23.5*60)
Dec sign will be based on + or - sign of Dec hours. + or - sign
of minutes and
seconds are ignored.
Lines starting with a semicolon = ; will be ignored.

ASCII input file for orbital element of comets. By using the
internal HNSKY editor you can check the syntax. File name
HNS_COM1.CMT. The format is defined in the first comment lines of
the provided samples. Lines starting with ; are interpreted as
comments.

ASCII input file for asteroids. By using the internal HNSKY editor
you can check the syntax. File name HNS_AST1.AST. The format is
defined in the first comment lines of the provided samples. Lines
starting with ; are interpreted as comments.

Visual field of view:The true angular diameter of the field as
seen true the telescope is mainly depending on the magnification
and the apparent field of the eyepc. For a plössl with apparent
field of about 50° the angular diameter is equal to
50°/magnification.

Visual field of view for a telescope with a focal length of 2000
mm:

Eye PC

Magnification

Type Plössl (50°)

Type Wide angle (67°)

40 mm

50 x

53'(44°)

80'

25 mm

80 x

38'

50'

20 mm

100 x

30'

40'

16 mm

125 x

24'

32'

10 mm

200 x

15'

20'

7 mm

286 x

10'

14'

Visual field of view for a telescope with a focal length of 1250
mm:

Eye PC

Magnification

Type Plössl (50°)

Type Wide angle (67°)

40 mm

31 x

85'(44°)

130'

25 mm

50 x

60'

80'

20 mm

63 x

48'

64'

16 mm

78 x

38'

52'

10 mm

125 x

24'

32'

7 mm

179 x

17'

22'

Visual field of view for a telescope with a focal length of 580
mm:

Eye PC

Magnification

Type Plössl (50°)

Type Wide angle (67°)

40 mm

15 x

176'(44°)

286'(exit pupil 6.7 mm)

25 mm

23 x

130'

175'(exit pupil 6 mm)

20 mm

29 x

103'

139'

16 mm

36 x

83'

112'

10 mm

58 x

52'

69'

7 mm

83 x

36'

48'

Note: 40 mm, 1-1/4" Plössl have a field of view of 44° only.

Photographic field of view: For a telescope with a 24 mm sensor,
the size of photographed part of the sky will be as follows:

The Comet and Asteroid routine use both an ASCII file which can be
accessed and updated under the main menu "FILE" and then "COMET
DATA EDITOR" or "ASTEROID DATA EDITOR", sub menu "TOOLS", option
"UPDATE FROM INTERNET".

A second and more convenient way are the update buttons in the
menu "SETTINGS", tab UPDATE:

The ephemerides of comets and asteroids (minor planets) are
calculated on the basis of the two body problem. Light speed
corrections will be applied, but perturbations by planets are not
taken into account. This means that the orbital elements of comets
and asteroids will be slowly influenced by the gravitational
forces of the planets in our solar system. As a result the
accuracy will drop slowly after a few months. You can download new
ephemerides as mentioned above or for asteroids you can use the
unique numerical integration routine inside HNSKY. Background
Without perturbations, the orbit of a asteroid or minor planet
around the Sun would follow an elliptical path around the Sun
according Kepler. Such an orbit can be accurately defined by the
six orbital elements: semi-major axis, eccentricity, inclination,
longitude of the ascending node, argument (longitude) of the
perihelion and the mean anomaly.

Gravitational perturbations by the major planets continuously
distort the ideal orbit and therefore change the orbital elements.
After few months perturbations can be up to 20 arc seconds in the
position.

The masses and locations of the perturbating major planets are
known, therefore the asteroid's change in speed and position can
be accurately calculated by the numerical integration of
acceleration/de-acceleration forces by the major planets. For any
other epoch and therefore new position and speed, a corresponding
set of orbital elements can be determined using the undisturbed
Kepler equations.

Functionality:
Select in the HNSKY editor a number of asteroids/minor planets and
with right mouse button menu select "Numerical integration".
Orbital element for the current epoch in HNSKY will be calculated.
Save to make permanent. Accuracy will be better then 1" over at
least 10 year time span. So in principle no download or update for
orbital elements for the next 10 years required!

Limitations:
The program can handle comet and asteroid ASCII files to more the
16 Mbyte, but above 10.000 objects it will slow down.

The comet orbital element parameters:

Here is an example of the orbital elements of the comet Halley in
1986:

T = The date of perihelion passage of the comet.
q = The distance of the comet from the Sun at the time of
perihelion passage, in astronomical units (AU).
e = The eccentricity of the comet's orbit. An eccentricity of 0.0
means that the orbit is circular, whilst a value of 1.0 indicates
a parabola. The majority of comets have an eccentricity between 0
and 1.
ω = The argument of perihelion, in degrees.
Ω = The longitude of the ascending node of the orbit, in degrees.
ι = The inclination of the orbit, in degrees.

Comet magnitude Parameters:

H = Is the absolute magnitude.
k = Is the activity factor which differs from one comet to
another. In general k is a number between 5 and 15.

The actual magnitude is calculated using the formula:

mag = H + 5*log10(delta) + k*log10(r). k is also given as g where
k:=2.5*g

'Delta' is the distance of the comet from the Earth (in
astronomical units) and 'r' is the distance of the comet from the
Sun (also in A.U.).

The asteroid orbital element parameters:

T = The reference date of the mean anomaly. The date at which the
asteroid has the mean anomaly specified by M
M = The mean anomaly of the asteroid at the reference date T, in
degrees.
a = The semi-major axis of the orbit, in astronomical units (AU).
e = The eccentricity of the orbit.
ω = The argument of perihelion, in degrees.
Ω = The longitude of the ascending node of the orbit, in degrees.
ι = The inclination of the orbit, in degrees.

Asteroid magnitude parameters:

H = Is the absolute visual magnitude.
G = Is the slope parameter

Comet and asteroid orbital elements are interchangeable. For
number crunchers only: conversion
The latest information of comets and minor planets can be
downloaded from the Minor Planet Center (MPC) Web
page. The official body that deals with astrometric
observations and orbits of minor planets (asteroids) and comets.
You can also import orbital elements for a single object from JPL Horizons.

1) Use JPL Horizons to produce orbital elements in your browser.
You get a pretty long output. Please select orbital elements and
not Observer Table. Ephemeris Type [change]:
ELEMENTS) 2) Select and copy the complete output to the Windows
clipboard or least all results.
3) Open the asteroid editor. CTRL+8
4) Use the special paste function (shift-V) and the converted
elements will be pasted.
5) Save if required.

The following lines in the clipboard will do. The blue marked will
be used, the rest will be ignored:

The orbital elements
consist of 6 quantities which completely define a circular, elliptic,
parabolic or hyperbolic orbit. Of these six, three describe the shape
and size of the orbit and the position of the object in the orbit and
the other three (i,Ω, ω) define the orientation of the orbit in space.

The program uses one common routine for both comets and asteroids and
selects an method of calculation (ellipse, parabola or hyperbola) based
on eccentricity. Since comets have typically a parabolic orbit which
have an infinite semi-major axis, the program first converts the
asteroids elements semi major axis (a) and mean anomoly (M) at an Epoch
to the perihelion date (T0) and the perihelion distance (q) typically
used for comets as follows:

To activate Bayer designations, the menu function "Name all stars" in
OBJECTS and "constellations" in SCREEN should be both on.

Bayer system of star designations:

In the year 1603, Bayer assigned to each constellation star a letter of
the Greek alphabet, beginning usually with Alpha for the brightest,
Beta for the second brightest, Gamma for the third, and so on till
Omega. In a few cases however, as in the Ursa Major, order of position
was used instead of order brightness. The Greek letter is followed by
the name of the constellation written in the possessive or genitive
form.

Examples: Alpha Lyrae, Beta Cephei.

Here is the Greek alphabet:

Letter

Name

Letter

Name

Α α

alpha

Ν ν

nu

Β β

beta

Ξ ξ

xi

Γ γ

gamma

Ο ο

omicron

Δ δ

delta

Π π

pi

Ε ε

epsilon

Ρ ρ

rho

Ζ ζ

zeta

Σ σ/ς

sigma

Η η

eta

Τ τ

tau

Θ θ

theta

Υ υ

upsilon

Ι ι

iota

Φ φ

phi

Κ κ

kappa

Χ χ

chi

Λ λ

lambda

Ψ ψ

psi

Μ μ

mu

Ω ω

omega

An other system devised by Flamsteed is using numbers. This is not
supported by HNSKY. Examples: 23 Orionis, 89 Virginis.

Back to the indexAbbreviations used for the visual deep sky description according Dreyer and others.

The visual description of the deep sky objects used in SAC are from the NGC,
some prominent amateurs, back issues of Deep Sky Magazine, Astronomy
magazine, Sky and Telescope magazine and Burnham's Celestial Handbook.
The descriptions are written down using the abbreviations from the NGC
and Burnham's. HNSKY will in most cases translate/decode the
abbreviations.

In some cases it will not be able to translate and will give the
original abbreviation. The abbreviations used are given below:

!

remarkable object

!!

very remarkable object

am

among

n

north

att

attached

N

nucleus

bet

between

neb

nebula, nebulosity

B

bright

P w

paired with

b

brighter

p

pretty (before F,B,L or S)

C

compressed

p

preceding

c

considerably

P

poor

Cl

cluster

R

round

D

double

Ri

rich

def

defined

r

not well resolved, mottled

deg

degrees

rr

partially resolved

diam

diameter

rrr

well resolved

dif

diffuse

S

small

E

elongated

s

suddenly

e

extremely

s

south

er

easily resolved

sc

scattered

F

faint

susp

suspected

f

following

st

star or stellar

g

gradually

v

very

iF

irregular figure

var

variable

inv

involved

nf

north following

irr

irregular

np

north preceding

L

large

sf

south following

l

little

sp

south preceding

mag

magnitude

11m

11th magnitude

M

middle

8...

8th magnitude and fainter

m

much

9...13

9th to 13th magnitude

If you have never dealt with the NGC abbreviations before, perhaps a few examples will help

1) The members of the Saguaro Astronomy Club (pronounced sa-war-oh) of
Phoenix. Who compiled the: SAC DEEP SKY DATABASE VERSION 8.1.. The
original SAC, SAO or PPM files (not in HNSKY format) are available at www.saguaroastro.org/content/downloads.htm

8) The organizations and many people behind:
http://simbad.u-strasbg.fr
http://archive.eso.org/
http://skyview.gsfc.nasa.gov

9) And finally some more books which where very useful:

The astronomical companion by Guy Ottewell. Very compact but full of
(technical) information to understand, enjoyment, as a reference and as
a none mathematical course in astronomy. Fourteenth printing 1995.

Download:Only required if you want the very best
accuracy for occultations or want planetary positions outside the 1750-2250 range of the internal solution.

Move mouse to one of the links below and with right mouse button and
select SAVE LINK AS... This will download the file. Only one file is
sufficient. You place the file either in the program folder typically \Program files\hnsky or at the document folder Documents\hnsky
Select the correct JPL_DE folder in HNSKY menu SETTINGS by double click
on the path and browse to the file. It is working if the capital
letters DE are shown in the (blue) title bar of HNSKY. If your outside
the time range, the letters DE will disappear. The program will use
then the default internal solution and give a warning message at the
status bar.

HNSKY comet and asteroid file updates. Updating is integrated in the
program.You could fownload them manually from: orbital elements in
formats suitable for loading into a variety of planetarium-type
computer programs", download the data in "TheSky" format from: http://cfa-www.harvard.edu/iau/Ephemerides/ Then copy and paste the data into the original files.